Modify attached Powershell script

We will need to change the following Powershell script according to our specifications. Script is on a link: [login to view URL] There will need to be added: -some additional textboxes (msExchExtensionAttribute1, msRTCSIP, set password never expires, fill proxyAddresses, mailnickname, MsExchExtensionCustomAttribute1, and make correction in some previous fields), some of them will be autogenerated, some clickable, some chooseable from data from XML file. We will specify them later in Excel file) -possibility to add group membership (security and distribution groups) -add CSV export/import for all selected data (including proxyaddresses etc) -code must be clean and well documented (for future expanding) and no data can be hardcoded- all must come from XML file